Various types of combat simulation systems are known for training soldiers and law enforcement officers. For example U.S. Pat. No. 4,487,583 by Brucker et al. discloses a weapons engagement simulation system in which a pulsed beam is generated from a simulated weapon which also incorporates the ability to fire blank charges. Users also wear a vest supporting an array of photodiodes thereon which are arranged to sense the light beam from the weapon directed upon the sensors. A hit is determined only if any single sensor receives an entire activation code within the pulsed beam. As shown in FIG. 7 of Brucker, hits are determined by individual hit detectors 66 which are each coupled to only one respective photodiode. To minimize interference from ambient light signals received upon the photodiodes which might represent erroneous hit signals, the pulsed beam must have a sufficient duration to define a sufficiently long and complex activation code. In the example by Brucker, several pulses with a two millisecond spacing are required to define an activation code which defines a hit signal. When firing a blank round together with a light beam being transmitted from the simulated weapon however, the recoil of the weapon from the blank round typically results in the light beam not being focussed on any single diode for a sufficient duration for the diode to receive the entirety of the activation code.
Another weapon engagement simulation system is disclosed in U.S. Pat. No. 7,872,849 by Elliott Jr. This system similarly comprises simulated weapons which generate light beams arranged to be detected by sensors on vests worn by the users. The sensors in this instance however comprise solar cells. When incorporating the firing of blank rounds together with a light beam emitting from the simulated weapon, the resulting recoil can cause the light beam to be displaced across the solar cells in a manner which results in the magnitude of light received at any one area of the solar cell being too weak to record a hit.
In other light based weapons engagement simulation systems, the recoil effect is compensated for by transmitting light in a cone shaped beam so that slight variations in the aiming of the simulated weapon resulting from recoil still maintains sufficient light at a single prescribed sensor for sufficient duration to activate a hit signal. The large cone shape required can result in determination of hits being received even when the actual centre of the cone representing the target location of the simulated weapon is offset and misaligned with the target sensors. Furthermore, the cone beam typically activates a large number of sensors such that subsequent pinpointing of the actual target location is difficult or impossible.